System and method for assisting with attachment of a stock implant to a patient tissue

ABSTRACT

A guide for assisting with attachment of a stock prosthetic implant to a patient tissue includes a lower guide surface configured to contact an upper implant surface of the stock prosthetic implant when a lower implant surface of the stock prosthetic implant contacts the patient tissue. An upper guide surface is accessible to a user when the lower guide surface is in contact with the upper implant surface. At least one guiding aperture extends through the guide body between the upper and lower guide surfaces at a predetermined aperture location with respect to the guide body and defines a predetermined target trajectory through the guide body. At least one of the target trajectory and the aperture location of each guiding aperture is preselected responsive to preoperative imaging of the patient tissue. A method of assisting with attachment of a stock prosthetic implant to a patient tissue is also provided.

RELATED APPLICATION

This application claims priority from U.S. Provisional Application No.61/408,324, filed Oct. 29, 2010, the subject matter of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a system and method for use of asurgical guide and, more particularly, to a system and method for use ofa surgical guide for assisting with attachment of a stock implant to apatient tissue.

BACKGROUND OF THE INVENTION

The efficient functioning of the hip joints is important to thewell-being and mobility of the human body. Each hip joint includes theupper portion of the femur, which terminates in an offset bony necksurmounted by a ball-headed portion known as the femoral head. Thefemoral head rotates within a socket, known as the acetabulum, in thepelvis to complete the hip joint. Diseases such as rheumatoid- andosteo-arthritis can cause erosion of the cartilage lining of theacetabulum so that the ball of the femur and the hip bone rub together,causing pain and further erosion. Bone erosion may cause the bonesthemselves to attempt to compensate for the erosion which may result inthe bone becoming deformed. This misshapen joint may cause pain and mayeventually cease to function altogether.

Operations to replace the hip joint with an artificial implant arewell-known and widely practiced. Generally, the hip prosthesis will beformed of two components, namely: an acetabular, or socket, componentwhich lines the acetabulum, and a femoral, or stem, component whichincludes a weight-bearing ball and replaces the femoral head. During thesurgical procedure for implanting the hip prosthesis, the remainingcartilage or damaged tissue is removed from the acetabulum using areamer such that the native acetabulum will accommodate the outersurface of the acetabular component of the hip prosthesis. Theacetabular cup component of the prosthesis can then be inserted into theprepared acetabulum. In some arrangements, the acetabular cup componentmay simply be held in place by a tight fit with the bone. However, inother arrangements, additional fixing means such as screws and/or bonecement may be used. The use of additional fixing means helps to providestability in the early stages after the prosthesis has been inserted. Insome modern prosthesis, the acetabular cup component may be coated onits external surface with a bone growth promoting substance which willencourage bone ingrowth which helps to hold the acetabular component inplace. The bone femoral head also is removed during the surgicalprocedure, and the femur shaft hollowed out using reamers and rasps toaccept the femoral component of the prosthesis. The stem portion of theprosthesis is inserted into the femur and secured therein to completethe hip joint replacement.

In order to strive toward desired performance of the combined acetabularand femoral hip prosthesis components, the acetabular cup portion mustbe properly positioned in the acetabulum. This is particularly importantsince incorrect positioning of the acetabular cup component can lead tothe prosthetic hip joint suffering from dislocations, a decreased rangeof motion, and possibly eventual loosening and/or failure of one or bothcomponents of the joint.

It is generally believed that there is a preferred orientation for theacetabular cup prosthesis component to provide a full range of motionand to minimize the risk of dislocation. Some example orientations ofthe acetabular cup prosthesis relative to the acetabular face are 45° to50° from the vertical and rotated forward to 15° to 20° of anteversion.This broadly replicates the natural angle of the acetabulum. However,the specific angular orientation of the acetabular cup portion variesfrom patient to patient.

In hip replacement surgery, the acetabular cup portion of the prosthesisis usually oriented in the acetabulum by using an acetabulum positioninginstrument. One example of such a positioner is a horizontal arm that isaligned parallel to a predetermined native tissue of the patient whenthe acetabular cup portion is oriented at a preferred abduction angle.This positioner is therefore sensitive to the position of the patient onthe operating table for accuracy. The acetabular cup placement istypically done using an acetabular cup positioner and visual adjustmentof the acetabular cup portion to ensure that the horizontal arm of thepositioner is approximately parallel to the selected reference tissue(or axis) of the patient. The user of the positioner may also view theposition of the acetabular cup portion relative to a second arm on theacetabular cup positioner which is positioned at a preset angle, toassist with positioning the acetabular cup at the correct abductionangle.

However, despite this known positioning procedure, the orientation ofthe acetabular cup portion in the replaced hip can deviate from thedesired orientation. This may be due to one or more factors. First, thepositioning of the acetabular cup is usually judged by eye. As theposition to be judged by the user is a compound angle, it may beparticularly difficult to visualize. Second, since the natural face ofthe acetabulum is not uniform and—where the hip is arthritic—may bedistorted by osteophytes, the acetabulum is not generally a reliableguide for orientating the acetabular cup portion of the prostheticjoint. A third problem is that the prior art mechanical alignment guidesusually rely on the pelvis being in a set position which may itself bedifficult to judge, particularly in an obese patient. In view of thesedifficulties, the acetabular cup portion may sometimes be actuallylocated via surgery as much as 20° from the desired/planned position.

The above factors and issues encountered in surgical hip interventionhave analogues in the shoulder surgery arena. For example, generally thenormal glenoid retroversion of a given patient may fall within a rangeof approximately 20° (5° of anteversion and 15° of retroversion). (Theversion of the glenoid is defined as the angle between the plane of theglenoid fossa and the plane of the scapula body.) In the pathologicstate, glenoid bone loss may result in a much larger range of versionangles.

One goal of shoulder surgery may be to modify the pathologic bone tocorrect pathologic version to be within the normal range or the normalversion of the patient's native anatomy before the bone loss occurred.During surgery, and particularly minimally invasive procedures, theplane of the scapula may be difficult or impossible to determine bydirect visual inspection, resulting in the need for assistive devices ormethods to define both the pathologic version present at the time ofsurgery and the intended correction angle.

It is generally believed that there is a preferred orientation for theglenoid component to provide a full range of motion and to minimize therisk of dislocation. Some example orientations of the glenoid prosthesisrelative to the glenoid face are about 5° of anteversion to about 15° ofretroversion; average version is about 1-2° of retroversion. Thisbroadly replicates the natural angle of the glenoid. However, thespecific angular orientation of the glenoid portion varies from patientto patient.

With a view to overcoming these disadvantages, some arrangements havebeen recently suggested in which a three-dimensional intraoperativecomputer imaging surgical navigation system is used to render a model ofthe patient's bone structure. This model is displayed on a computerscreen and the user is provided with intraoperative three-dimensionalinformation as to the desired positioning of the instruments and theglenoid component of the prosthetic implant. However, surgicalnavigation arrangements of this type are not wholly satisfactory sincethey generally use only a low number of measured landmark points toregister the patient's anatomy and to specify the angle of theprosthetic implant component (e.g., a glenoid component), which may notprovide the desired level of accuracy. Further, the information providedby such systems may be difficult to interpret and may even provide theuser with a false sense of security. Moreover, these systems aregenerally expensive to install and operate and also have high usertraining costs. Various proposals for trial prosthetic joint componentshave been made in an attempt to overcome the problems associated withaccurately locating the acetabular cup portion of the prostheticimplant. While these trial systems may help with checking whether theselected position is correct, they are not well-suited to specify thecorrect position initially, and thus there still is user desire for asystem which may assist a user in placement of prosthetic implantcomponent in a prepared native tissue site.

SUMMARY OF THE INVENTION

In an embodiment of the present invention, a method of attaching a stockprosthetic implant to a patient tissue is described. The stockprosthetic implant includes a plurality of fastener apertures extendingtherethrough. A lower implant surface of the stock prosthetic implant isplaced into contact with the patient tissue in a predetermined implantorientation. A guide having a lower guide surface contoured tosubstantially mate with at least a portion of an upper implant surfaceof the stock prosthetic implant, an upper guide surface spacedlongitudinally apart from the lower guide surface by a guide body, andat least one guiding aperture extending through the guide body betweenthe upper and lower guide surfaces at a predetermined aperture locationwith respect to the guide body is provided. A predetermined targettrajectory is defined through the guide body with a chosen guidingaperture. At least one of the target trajectory and the aperturelocation of each guiding aperture is preselected responsive topreoperative imaging of the patient tissue. The lower guide surface isplaced into mating contact with at least a portion of the upper implantsurface in a predetermined relative guide/implant orientation. Thechosen guiding aperture is placed into a collinear relationship with achosen one of the fastener apertures. A surgical tool is guided throughthe chosen guiding aperture and the corresponding chosen fasteneraperture and inserting the surgical tool into the patient tissue alongthe target trajectory to create a fastener cavity in the patient tissue,and/or a fastener is guided through the chosen fastener aperture andinto the patient tissue along the target trajectory.

In an embodiment of the present invention, a guide for assisting withattachment of a stock prosthetic implant to a patient tissue isdescribed. A lower guide surface is configured to contact an upperimplant surface of the stock prosthetic implant when a lower implantsurface of the stock prosthetic implant is in contact with the patienttissue. At least a portion of the lower guide surface is contoured tosubstantially mate with at least a portion of the upper implant surface.An upper guide surface is spaced longitudinally apart from the lowerguide surface by a guide body. The upper guide surface is accessible toa user when the lower guide surface is in contact with the upper implantsurface. At least one guiding aperture extends through the guide bodybetween the upper and lower guide surfaces at a predetermined aperturelocation with respect to the guide body. The at least one guidingaperture defines a predetermined target trajectory through the guidebody. The at least one guiding aperture is collinear with acorresponding at least one fastener aperture in the stock prostheticimplant when the lower guide surface is mated with the upper implantsurface. At least one of the target trajectory and the aperture locationof each guiding aperture is preselected responsive to preoperativeimaging of the patient tissue.

In an embodiment of the present invention, a guide for assisting withattachment of a stock prosthetic implant to a patient tissue isprovided. A lower guide surface is configured to contact an upperimplant surface of the stock prosthetic implant when a lower implantsurface of the stock prosthetic implant is in contact with the patienttissue. The lower guide surface is contoured to substantially mate withat least a portion of the upper implant surface. An upper guide surfaceis spaced longitudinally apart from the lower guide surface by a guidebody. The upper guide surface is accessible to a user when the lowerguide surface is in contact with the upper implant surface. An orientingfeature is configured to enter a predetermined orienting relationshipwith a previously placed landmark while the lower guide surface is inmating contact with at least a portion of the upper implant surface in apredetermined relative guide/implant orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference may be made tothe accompanying drawings, in which:

FIG. 1 is a top view of a first example use environment;

FIG. 2 is a top view of a first prior art prosthetic component;

FIG. 3 is a side view of the prior art prosthetic component of FIG. 2;

FIG. 4 is a top view of a first embodiment of the present invention in afirst configuration;

FIG. 5 is a perspective bottom view of the embodiment of FIG. 4 in thefirst configuration;

FIG. 6 is a top view of the embodiment of FIG. 4 in a secondconfiguration;

FIG. 7 is a bottom view of the embodiment of FIG. 6 in the secondconfiguration;

FIG. 8 is a top view of the embodiment of FIG. 4 in a thirdconfiguration;

FIG. 9 is a top view of the embodiment of FIG. 4 in a fourthconfiguration;

FIG. 10 is a top view of the embodiment of FIG. 4 in a fifthconfiguration;

FIG. 11 is a schematic cross-sectional side view of the embodiment ofFIG. 4 in any of the first through fifth configurations;

FIG. 12 is a top view of an example use environment for the embodimentof FIG. 4 as a prepared surgical site;

FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12;

FIG. 14 is a top view of the example use environment of FIG. 12 with theaddition of a schematic top view of the embodiment of FIG. 4;

FIG. 15 is a cross-sectional view taken along line 15-15 of FIG. 14;

FIGS. 16-21 are schematic cross-sectional views of a sequence ofoperation of the embodiment of FIG. 4;

FIG. 22 is a top view of a second example use environment;

FIG. 23 is a top view of a second prior art prosthetic component;

FIG. 24 is a side view of the prior art prosthetic component of FIG. 23;

FIG. 25 is a top view of a second embodiment of the present invention;

FIG. 26 is a bottom view of the embodiment of FIG. 25;

FIG. 27 is a perspective view of the embodiment of FIG. 25 in the secondexample use environment of FIG. 22;

FIG. 28 is a schematic side view of a third embodiment of the presentinvention in an example use environment; and

FIG. 29 is a front view of the embodiment of FIG. 28.

DESCRIPTION OF EMBODIMENTS

FIG. 1 depicts a portion of the external surface of a (left) hip bone100, which is an example of a possible patient tissue use environmentfor the described systems, apparatuses, and methods. Directional arrow102 indicates the superior/inferior and anterior/posterior directions.The body of ischium, body of ilium, and body of pubis are showngenerally at 104, 106, and 108, respectively. The acetabulum 110, whichis formed in part by these three bodies 104, 106, and 108, has arecessed acetabular fossa 112 and is surrounded by an acetabular margin114 (shown approximately in FIG. 1 via dashed line).

The patient tissue is shown and described herein at least as a hip boneand the implant component is shown and described herein at least as anacetabular prosthetic hip component, but the patient tissue andcorresponding implant component could be any desired types such as, butnot limited to, hip joints, shoulder joints, knee joints, ankle joints,phalangeal joints, metatarsal joints, spinal structures, long bones(e.g., fracture sites), or any other suitable patient tissue useenvironment for the present invention. For example, the implantcomponent could be an internal fixation device (e.g., a bone plate), astructure of a replacement/prosthetic joint, or any other suitableartificial device to replace or augment a missing or impaired part ofthe body. The implant component will be described herein as a prostheticimplant component.

The term “lateral” is used herein to refer to a direction indicated bydirectional arrow 102 in FIG. 1; the lateral direction in FIG. 1 liessubstantially within the plane of the drawing and includes all of thesuperior, inferior, anterior, and posterior directions. The term“longitudinal” is used herein to refer to a direction definedperpendicular to the plane created by directional arrow 102, with thelongitudinal direction being substantially into and out of the plane ofthe drawing in FIG. 1 and representing the proximal (toward the medialline of the body) and distal (out from the body) directions,respectively.

FIGS. 2 and 3 are side and top views, respectively, of a prior art stockprosthetic implant, and, more specifically, of a stock acetabular cupimplant 216 of a stock hip prosthesis. The term “stock” is used hereinto indicate that the prosthetic component indicated is notcustom-manufactured or -configured for the patient, but is insteadprovided as a standard inventory item by the prosthetic manufacturer. Aparticular stock component may be selected by the user from a productline range of available components, with the user specifying a desiredconfiguration, general size (e.g., small, medium, large), material, orany other characteristic of the component. Indeed, the stock componentmay be manufactured only after the user has selected the desired optionsfrom the range of choices available. However, the stock component isdifferentiated from a custom-manufactured or bespoke component in thatthe stock component is agnostic and indifferent regarding a particularpatient anatomy during the design and manufacturing processes for aprosthetic implant intended for that patient, while the patient anatomyis an input into at least one design and/or manufacturing process for acustom-manufactured component. The following description presumes theuse of a stock prosthetic component, though one of ordinary skill in theart will be able to provide for the use of the present invention with acustom-manufactured component, instead.

The acetabular cup implant 216 comprises a parti-spherical acetabularshell 218 and a plurality of prosthetic apertures, described herein asfastener apertures 220, extending through the thickness of theacetabular shell between an upper implant surface 222 and a lowerimplant surface 224. The below description of “fastener apertures” 220does not presume that each of such are configured and/or intended toactually receive a fastener, but is done solely for ease of descriptionherein. The acetabular cup implant 216 is generally made from metal oranother durable, biocompatible material and is fastened securely into anacetabulum 110 during a hip replacement procedure. An acetabular liner(not shown), generally made of a polymer or another material havingdesirable lubricity and durability properties, is then attached withinthe acetabular shell 218 and the acetabular liner cradles the femoralball component (not shown) in the finished prosthetic hip joint. Thefastener apertures 220 are configured to accept fasteners (not shown),and the acetabular shell 218 usually includes more fastener cavitiesthan the number of fasteners expected to be used, to provide flexibilityfor the user in selecting fastener placement for a particular patient.The multiplicity of fastener apertures 220, beyond the number intendedto receive fasteners, also may provide advantages in weight savings andincreased flexibility of the acetabular cup implant 216.

Much of the success of a prosthetic joint replacement arises from secureaffixation of the acetabular cup implant 216 to the hip bone 100, andanchoring of the fasteners into robust bony matter contributes to asuitably snug fit between the acetabular cup implant and the hip bone.However, pathological anatomy of the hip bone 100 may affect where thefasteners can be securely placed. The native and pathological anatomiesdiffer from patient to patient, so preoperative patient imaging scansmay be used to preoperatively plan desired locations and trajectoriesfor the fasteners to be inserted through the emplaced acetabular cupimplant 216 into the hip bone 100. However, and particularly duringminimally invasive surgeries, very little of the hip bone 100 is visibleto the user, and the visible portion of the hip bone may be located atthe distal end of a “tunnel” of surrounding soft tissue temporarilycleared out of the way by the user; accordingly, available maneuveringspace at the surgical site may be severely restricted. In addition, thepatient's hip joint may be actually canted slightly differently duringthe surgical procedure than planned preoperatively. These are among thefactors which may result in a preoperative location/trajectory plan fora particular fastener being very difficult and time-consuming for a userto actually perform in an operative environment.

To aid with carrying out a preoperative plan for attaching a stockprosthetic implant to a patient tissue, a guide 426 may be provided,according to a first embodiment of the present invention. The guide 426,shown in various optional configurations in FIGS. 4-10, is at leastpartially custom-manufactured for a particular patient responsive topreoperative imaging of the patient tissue. For example, the guide 426may be wholly custom-made (e.g., using rapid prototyping techniques) ormay be modified from a stock guide or guide blank (not shown). It iscontemplated that at least a part of the guide 426 is apatient-specific, single-use, bespoke feature suited only for use at theindicated surgical site, though one of ordinary skill in the art couldcreate a guide (not shown) which uses a patient-specific “disposable”structure connected to a stock, generic “reusable” carrier.

Regardless of the whole/partial custom manufacture status, the guide 426may be configured responsive to at least one of preoperative imaging ofthe patient tissue and preoperative selection of the stock prostheticimplant. The location and target trajectory of each fastener of theimplant are predetermined by a user before the guide 426 is associatedwith the patient tissue. This predetermination may occurintraoperatively, as the user is able to directly see the condition ofthe surgical site. However, it is contemplated that a predeterminationof the desired insertion location and target trajectory of each fastenercould be accomplished preoperatively, with reference to preoperativeimaging of the patient tissue. For example, a system similar to that ofco-pending U.S. patent application No. to be determined, filed Oct. 27,2011, titled “System of Preoperative Planning and Provision ofPatient-Specific Surgical Aids” and claiming priority to U.S.Provisional Patent Application No. 61/408,392, filed Oct. 29, 2010 andtitled “System of Preoperative Planning and Provision ofPatient-Specific Surgical Aids”, the entire contents of both of whichare incorporated herein by reference, or any suitable preoperativeplanning system, could be used. In this manner, a user can create apatient tissue model for observation, manipulation, rehearsal, or anyother pre-operative tasks.

The term “model” is used herein to indicate a replica or copy of aphysical item, at any relative scale and represented in any medium,physical or virtual. The patient tissue model may be a total or partialmodel of a subject patient tissue, and may be created in any suitablemanner. For example, and as presumed in the below description, thepatient tissue model may be based upon computer tomography (“CT”) dataimported into a computer aided drafting (“CAD”) system. Additionally oralternatively, the patient tissue model may be based upon digital oranalog radiography, magnetic resonance imaging, or any other suitableimaging means. The patient tissue model will generally be displayed forthe user to review and manipulate preoperatively, such as through theuse of a computer or other graphical workstation interface.

During preoperative planning, the user can view the patient tissue modeland, based upon knowledge of other patient characteristics (such as, butnot limited to, height, weight, age, and activity level), then choose adesired stock prosthetic implant. Because three-dimensional image modelsare available of many stock prosthetic implants, the user may be able to“install” the stock prosthetic implant virtually in the patient tissuemodel via a preoperative computer simulation. During such a simulation,the user can adjust the position of the stock prosthetic implant withrespect to the patient tissue, even to the extent of simulating thedynamic interaction between the two, to refine the selection, placement,and orientation of the stock prosthetic implant for a desired patientoutcome.

Once a chosen stock prosthetic implant has been virtually placed in adesired position and orientation with respect to the patient tissue (itwill be understood that some mechanical modification might need to bemade to the native patient tissue to accomplish this implant placement),the fastener placement can also be planned through the use of thecomputer simulation, with consideration of the location, amount, andpathology of the patient tissue, or any other desired factors, beingtaken into account in fastener placement planning. By hand and/or withautomatic computer assistance, the user can experiment with variousfastener sizes, placements, and orientations for securing the stockprosthetic implant to the patient tissue. When the fastener positioninghas been finalized, with the implant virtually positioned in apredetermined implant orientation with respect to the patient tissue, alocation and target trajectory can be defined for each of the fastenersto follow during installation. The term “trajectory” is used herein toindicate an invisible line along which an elongate body will travelunder guidance from the trajectory-defining structure.

The fastener location and target trajectory information for theparticular patient tissue achieved via preoperative imaging and/orcomputer simulation/modeling may be transferred to a physical aid forthe user through the custom manufacture of a guide 426, such as thoseshown in various configurations in FIGS. 4-10. When the preoperativeplanning has been finalized, a virtual guide 426 is generated at apredetermined guide orientation with respect to the virtual implant andthe virtual patient tissue. The user may then have the opportunity toadjust the virtual guide 426, if desired, before a physical guide 426 isproduced.

With reference to FIGS. 4-5, the guide 426 (hereafter described as beingphysical, not virtual) includes a lower guide surface 528 (visible inFIG. 5) configured to contact an upper implant surface 222 of the stockprosthetic implant, here presumed to be an acetabular cup implant 216,when the lower implant surface 224 is in contact with the acetabulum110. At least a portion of the lower guide surface 528 is contoured tosubstantially mate with at least a portion of the upper implant surface222, as will be discussed below. The term “mate” is used herein toindicate a relationship in which the contours of two structures are atleast partially matched or coordinated in at least two dimensions. Forexample, both the lower guide surface 528 and the upper implant surface222 could have profiles that are concavely curved, convexly curved,planar/linear, or any combination of those or other profile shapes. Theguide 426 also includes an upper guide surface 430 spaced longitudinallyapart from the lower guide surface 528 by a guide body 432. The upperguide surface 430 is accessible to a user when the lower guide surface528 is in contact with the upper implant surface 222.

The patient's name, identification number, surgeon's name, and/or anyother desired identifier may be molded into, printed on, attached to, orotherwise associated with the guide 426 in a legible manner. The guide426 may be made by any suitable method such as, but not limited to,selective laser sintering (“SLS”), fused deposition modeling (“FDM”),stereolithography (“SLA”), laminated object manufacturing (“LOM”),electron beam melting (“EBM”), 3-dimensional printing (“3DP”), contourmilling from a suitable material, computer numeric control (“CNC”),other rapid prototyping methods, or any other desired manufacturingprocess.

At least one guiding aperture 434 extends through the guide body 432between the upper and lower guide surfaces 430 and 528 at apredetermined aperture location with respect to the guide body (i.e., apredetermined placement of the guiding aperture 434 on the guide body).As shown in FIGS. 4-5, the at least one guiding aperture 434 defines apredetermined target trajectory 536 through the guide body 432. At leastone of the target trajectory 536 and the aperture location of eachguiding aperture 434 can be preselected responsive to preoperativeimaging of the patient tissue, as previously described. When the guide426 is placed atop the acetabular cup implant 216 as described above(with the lower guide surface 528 substantially mated with at least aportion of the upper implant surface 222), at least one of the guidingapertures 434 is collinear with a corresponding fastener aperture 220 inthe acetabular cup implant, as will be discussed below. The term“collinear” is used herein to indicate that central axes of each of twostructures lie along the same line. However, the diameters of the“collinear” guiding apertures 434 and fastener apertures 220 coulddiffer from each other. In short, the aperture locations of the guidingapertures 434 are preselected to facilitate placement of a fastener intothe stock prosthetic implant (e.g., the acetabular cup implant 216 forthe embodiment of FIGS. 4-10) and the underlying patient tissue at apreselected fastener location and a preselected fastener trajectoryafter removal of the guide 426 from the stock prosthetic implant.

The lower guide surface 528 shown in FIG. 5 includes at least onelocating protrusion 538. Each of the locating protrusions 538, whenpresent, extends from the lower guide surface 528 and is configured tonest into, or mate with, a preselected fastener aperture 220 of theacetabular cup implant 216, to assist with mating of the lower guidesurface with at least a portion of the upper implant surface 222. As canbe seen in FIG. 5, the locating protrusions 538 in the depictedembodiment are simple protrusions and are not configured to accept afastener.

An orienting feature 440, such as the depicted extension in FIGS. 4-5,may be provided to the guide 426. As shown here, for use with theacetabular cup implant 216, the orienting feature 440 may extend,perhaps substantially, longitudinally and/or laterally from the guide426, but the direction, amount, and type of extension will depend uponthe location and type of body tissue with which the guide 426 is beingused. The orienting feature 440 may be configured to enter apredetermined orienting relationship with a landmark (not shown), suchas a guide pin, wire, marking, and/or other location indicatorpreviously placed in a predetermined relationship with the patienttissue, such predetermined orienting relationship occurring when thelower guide surface 528 is in mating contact with at least a portion ofthe upper implant surface 222 in a predetermined relative guide/implantorientation. (The predetermined relative guide/implant orientation isachieved when the guide 426 and acetabular cup implant 216 are mated ina desired manner, as predetermined via preoperative imaging and/oranalysis.) The landmark may be any suitable two- or three-dimensionallandmark such as, but not limited to, a native or acquired anatomicalfeature of the patient tissue and/or a separately provided landmarkplaced with the assistance of a guide as disclosed in co-pending U.S.patent application No. to be determined, filed Oct. 27, 2011, titled“System and Method for Association of a Guiding Aid with a PatientTissue” and claiming priority to U.S. Provisional Patent Application No.61/408,359, filed Oct. 29, 2010 and titled “System and Method forAssociation of a Guiding Aid with a Patient Tissue”, the entire contentsof both of which are incorporated herein by reference. The landmarkcould also or instead be placed using a robotic surgical aid, adjustablereusable (e.g., “dial-in”) tools, intraoperative imaging, or any othersuitable placement aid. For example, a portion of the orienting feature440 could be configured to mate with a preselected surface of thepatient tissue acting as a landmark such that the mating of theorienting feature and the patient tissue indicates that thepredetermined orienting relationship between the orienting feature andthis patient tissue landmark has been achieved.

Optionally, an original landmark could have been previously placed, thenremoved for any reason (e.g., to facilitate machining of the acetabulum110 surface). A second landmark may then be placed at the same locationand with the same location as the original landmark, such as via reusingthe cavity in the surface left by the removal of the original landmark.Indeed, the remaining cavity in the surface itself may serve alandmarking function. Through these or any other such transformations ofphysical manifestations, the position information represented by theoriginal landmark and preoperatively planned may be preserved and usedduring various stages of the surgical procedure regardless of the way inwhich that position landmark is made available to the user at thosevarious stages. Optionally, the orienting feature 440 may include anorienting indicator 442. When present, the orienting indicator 442 maybe configured to achieve a predetermined signaling relationship (thesignaling relationship being directly related to the orientingrelationship) with the landmark, as will be described below, while theguide 426 and the stock prosthetic implant—here, the acetabular cupimplant 216—are in the predetermined relative guide/implant orientation.For example, in the first configuration of the first embodiment shown inFIGS. 4-5, the orienting feature 440 is a bridge-type structureextending from the guide body 432 and the orienting indicators 442 arenotches in the orienting feature 440, each shaped to somewhat closelysurround at least a portion of the diameter of a guide pin or otherthree-dimensional landmark to achieve the predetermined signalingrelationship. The landmark(s) were previously placed in any suitablemanner in predetermined locations at the surgical site. Accordingly, thepredetermined signaling relationship between the landmark(s) and theorienting indicator(s) 442 assists the user in placing the guide 426into a predetermined guide orientation with respect to the patienttissue.

When the guide 426 and the stock prosthetic implant are held in apredetermined relative guide/implant orientation (e.g., through the useof locating protrusions 538, frictional engagement, any other mechanicallinkage [e.g., nesting], or even merely coordinated movement of each bythe user), then the stock prosthetic implant is manipulated in concertwith the guide. Accordingly, movement of the guide 426 into thepredetermined guide orientation—as signaled by coordination of thelandmark(s) and the orienting feature 440—will concurrently move thestock prosthetic implant into a predetermined implant orientation withrespect to the patient tissue.

One of ordinary skill in the art can readily preoperatively plan theplacement and type of landmark(s), as well as the structure and type oforienting feature(s) 440 and/or orienting indicator(s) 442 to assist theuser in guiding the stock prosthetic implant into the predeterminedimplant orientation and/or location with respect to the patient tissuefor a particular application of the present invention.

While the orienting indicator 442 is shown in FIGS. 4-5 as being anotch, any suitable structure, notch-like or otherwise, could be used asan orienting indicator. For example, the orienting indicator 442 couldbe a lug extending from the orienting feature 440, a visual indicatorsuch as a line drawn or etched on the orienting protrusion, or even amechanical system such as a latch or trip-wire.

As another example, a second configuration of the first embodiment ofthe present invention is shown in FIGS. 6-7. Structures of FIGS. 6-7that are the same as or similar to those described with reference toFIGS. 4-5 have the same reference numbers. As with all alternateconfigurations shown and described herein, description of commonelements and operation similar to those in previously describedconfigurations will be omitted, for clarity. In the secondconfiguration, the guide 426 includes multiple locating protrusions 538and multiple orienting features 440. One of the orienting features 440includes a notchlike orienting indicator 442 a configured to interactwith a landmark in an active (e.g., mechanically interacting) signalingrelationship, and the other of the orienting features 440 includes amore passive orienting indicator 442 b, which is depicted here as aninscribed line on the orienting feature and is configured to provide amore passive (e.g., visually observed) signaling relationship with alandmark.

As depicted in FIGS. 6-7, the guide 426 may include at least one centralguide aperture 644 extending through the guide body 432 between theupper and lower guide surfaces 430 and 528. The central guide aperture644 may be configured to accept a landmark placed in a predeterminedrelationship with the patient tissue. For example, the central guideaperture 644 of the second configuration is substantially centrallylocated in the guide body 432. If a central landmark (not shown) isplaced in a similarly central location of the patient tissue at thesurgical site and accepted through the central guide aperture 644, theguide body 426 could pivot about that central landmark (as if on anaxis) under rotational force exerted by the user. In such manner, theguide 426 (and, by extension, the stock prosthetic implant when held inthe predetermined relative guide/implant relationship) can initially beplaced in a desired position with respect to the patient tissue—agnosticof rotational orientation—and then the rotational orientation can be setvia pivoting of the guide and stock prosthetic implant about the centrallandmark until the orienting feature 440 achieves the predeterminedorienting relationship with an other landmark, spaced apart from thecentral landmark. Optionally the central landmark could be a guidewire(not shown), such as that disclosed in co-pending U.S. patentapplication Ser. No. 13/178,324, titled “Method and Apparatus forProviding a Relative Location Indication During a Surgical Procedure”and filed Jul. 7, 2011, the entire contents of which are incorporatedherein by reference.

As an alternative to this agnostic placement of the guide 426 andnested/attached stock prosthetic implant at the surgical site andsubsequent rotation into position, the guide 426 and the stockprosthetic implant could be concurrently placed into contact with atleast one landmark (which could include the central landmark) at alocation spaced apart from the patient tissue at the surgical site. Forexample, a landmark could be an elongate guide pin, and a notch-likeorienting indicator 442 could be placed into the signaling relationshipwith a protruding end of the guide pin some distance from the patienttissue. In this optional situation, the stock prosthetic implant wouldbe guided into the predetermined implant orientation concurrently withbeing brought into contact with the patient tissue as the orientingindicator 442 slides along the length of the guide pin via a rail-likedynamic guiding technique.

FIGS. 8, 9, and 10 depict third, fourth, and fifth configurations,respectively, of the first embodiment of the present invention. In thethird configuration of FIG. 8, the guide 426 is configured tosubstantially mate with a fairly large portion of the acetabular cupimplant 216. Relief slots 846 may extend laterally inward from an outerguide rim 848 and, when present, can help provide for a temporaryreduction in circumference of the guide 426 under lateral force (e.g., asqueeze by the user) to elastically deform the guide 426 and facilitateplacement of the guide into the acetabular cup implant 216. When thelateral force is released, the guide 426 expands back to the originalcircumference to nest closely within the acetabular cup implant 216.

As shown in FIG. 8, a plurality of two-dimensional orienting features440 are provided on the upper guide surface 430. The orienting features440 shown in FIG. 8 are visual indications—here, darkened carets—on theouter guide rim 848 and may help guide the user in placing the guide 426in a predetermined mating relationship with the stock prostheticimplant, to assist in carrying out the preoperative plan including theplacement of the fasteners to secure the stock prosthetic implant in adesired manner. For example, the orienting features 440 shown in FIG. 8may be placed to correspond to (e.g., line up radially with) thepositions of one or more landmarks previously placed on or near theacetabulum 110. Optionally, the orienting features 440 may be placed tocorrespond to the position(s) of one or more landmarks previously placedon the acetabular cup implant 216, to help orient the guide 426 into thepredetermined relative guide/implant relationship with the stockprosthetic implant. This orientation between the guide 426 and theacetabular cup implant 216 may be especially important when the guideand acetabular cup implant are held relatively firmly to one anotherduring their insertion to the surgical site.

The guides 426 in FIGS. 9 and 10 each are configured to substantiallymate with a much smaller portion of the acetabular cup implant 216 thanare the guides of FIGS. 4-8. The guide 426 of the fourth configuration,shown in FIG. 9, is shaped like a segment of a circle and may includeone or more laterally oriented locating protrusions 538 that help steadyand/or position the guide at a desired position on the acetabular cupimplant 216. When present, the locating protrusions 538 may contact theacetabular cup implant 216 at a predetermined position to indicate thatthe guide 426 is placed correctly on the acetabular cup implant, whichcould include a structure (not shown) configured to engage with thelocating protrusions. The guide 426 of FIG. 9 might be placedasymmetrically upon the acetabular cup implant 216, with the outer guiderim 848 being aligned with an outer rim of the acetabular cup implant.

Similarly to the guide 426 of FIG. 9, the guide 426 of the fifthconfiguration, shown in FIG. 10, is substantially shaped as a portion ofa spherical shell and might be placed in any desired orientation on theacetabular cup implant 216 which would result in the desired fastenerplacement. As can be seen in FIG. 10, locating protrusions 538 mayextend from any surface of the guide 426. For example, at least onelocating protrusion 538 of FIG. 10 extends downward from the lower guidesurface 528, toward the upper implant surface 222 when the guide 426 ismated with the acetabular cup implant 216. A locating protrusion 538extending in this orientation may be configured to nest into apreselected one of the fastener apertures 220 to provide positivelocation and increased stability between the guide 426 and theacetabular cup implant 216.

FIG. 11 illustrates, in schematic cross-section, an example of the guide426 being used to define the predetermined target trajectories 536 andaperture locations, with fasteners 1150 being temporarily placed throughselected ones of the guiding apertures 434 in FIG. 11 to show the targettrajectories' role in guiding fasteners, be they screws, nails, brads,rods, or any other suitable fasteners. It is contemplated, though, thatin most use environments, the guide 426 will be removed from theacetabular cup implant 216 before fasteners 1150 are installed on theacetabular cup implant.

It is apparent from FIG. 11 that the guide body 432 should be thickenough that each of the guiding apertures 434 can influence thetrajectory of an elongate body passing therethrough. If the guide body432 is too thin, the elongate body may precess within the guidingaperture 434 and deviate from the target trajectory 536. The elongatebody intended for insertion through the guiding apertures 434 could be afastener, a surgical tool, a guide pin, or any other suitable structure,and could be of any suitable size with respect to a correspondingguiding aperture 434 and/or fastener aperture 220. The elongate bodycould contact all, a portion of, or none of the inner walls of theguiding aperture 434 and/or fastener aperture 220, as desired.

At least one depth limiting feature 1152 may be provided to the guide426 to limit further motion of the elongate body along the targettrajectory and into the patient tissue past a predetermined depth. Whenthe elongate body is a surgical tool, for example, the depth limitingfeature 1152 may be a blocking stud, as shown in FIG. 11, which“catches” a drill chuck, a reamer shoulder, or another structureassociated with the surgical tool when the surgical tool has reached thepredetermined depth. It is contemplated that the depth limiting feature1152 might be custom-designed and -manufactured for that particularpatient tissue with the assistance of preoperative imaging. The depthlimiting feature 1152 may also or instead be provided by the fastener1150, such as, but not limited to, a head of the fastener having adiameter greater than the shaft and preventing the fastener head frompassing through the fastener aperture 220—in this example, the depthlimiting feature is the fastener head and may be adequately provided bya stock fastener.

FIGS. 12-15 show top and cross-sectional side views of a portion of asurgical procedure in which the guide 426 may assist with providingtarget trajectories 536 and locations for fasteners 1150 to secure anacetabular cup implant 216 to an acetabulum 110. In FIGS. 12-13, thedistal ends of three landmarks 1254 (shown here as guide pins) have beenplaced in the hip bone 100 in or near the acetabulum 110 (optionallywith the assistance of a pin guide, not shown). The acetabular cupimplant 216 has been placed in contact with a prepared acetabulum 110.Here, the acetabular cup implant 216 includes orienting features 440 ato help the user rotationally orient the acetabular cup implant with thevisual assistance of the two landmarks 1254 located outside theacetabulum 110 on the hip bone 100. The orienting features 440 a mightnot be used for situations in which the acetabular cup implant 216 isrotationally symmetrical, but could be provided even with a symmetricalacetabular cup implant for any other desired reason.

Additionally, in FIGS. 12-13, a chosen one of the fastener apertures 220of the acetabular cup implant 216 has been passed or slid over at leasta portion of a landmark 1254 (which may be a central landmark, as shown)previously placed in the acetabulum 110 to help orient the acetabularcup implant within the acetabulum. Incidentally, this central landmarkmight have been used to help prepare the acetabulum 110, such as byguiding a reamer (not shown) to ream the acetabulum into a morestandardized spherical shape to accept the stock acetabular cup implant216. Optionally, this chosen one of the fastener apertures 220 maydiffer in size, shape, or any other characteristic from the otherfastener apertures, to indicate and/or facilitate its use with thecentral landmark 1254. At the stage shown in FIGS. 12-13, the acetabularcup implant 216 is either sitting loosely in the acetabulum 110 or has atenuous press-fit relationship with the acetabulum—in any case, therehave been no fasteners 1150 installed, and the acetabular cup implant216 is thus not yet a functional portion of a prosthetic hip joint.

FIGS. 14-15 show the hip bone 100 and acetabular cup implant 216 ofFIGS. 12-13 with the addition of an overlying guide 426 according to thepresent invention. Similar to the orientation of the acetabular cupimplant 216, the guide 426 in FIGS. 14-15 has a guiding aperture 434which been passed or slid over at least a portion of the centrallandmark 1254 previously placed in the acetabulum 110 to help achieve apredetermined guide orientation within the acetabular cup implant. Theguide 426, as shown, includes inscribed orienting features 440 b (todistinguish from the orienting features 440 a of the acetabular cupimplant 216) which help rotationally orient the acetabular cup implantwith the assistance of the two landmarks 1254 located outside theacetabulum 110 on the hip bone 100. The guide 426 of FIGS. 14-15 alsoincludes a bridge-like orienting feature 440 including orientingindicators 442 which are in the signaling relationship with two of thelandmarks 1254 in the pictured view. Optionally and as previouslydiscussed, at least a portion of the bridge-like orienting feature 440could include a shaped profile (not shown) which achieves the signalingrelationship through mating with a preselected portion of the patienttissue.

The stock acetabular cup implant 216 has a predetermined number offastener apertures 220, at least one of which may be extraneous, aspreviously discussed. The guide 426 also has a predetermined number ofguiding apertures 434, which may be any number, but is contemplated tobe no more than the predetermined number of fastener apertures 220 inthe acetabular cup implant. At least one guiding aperture 434 should becollinear or otherwise coincident in some physical property with apredetermined one of the fastener apertures 220. In this manner, theguide 426 acts as a “mask” to obscure those fastener apertures 220 whichare not predetermined to receive a fastener 548, while providing alocation and target trajectory 536 for installation of fasteners 1150into those fastener apertures which are to be used in securing theacetabular cup implant 216 to the hip bone 100.

As is apparent from the cross-sectional view of FIG. 15, the locatingprotrusions 538 on the underside of the guide 426 each nest intopreselected ones of the fastener apertures 220 to help provide positivelocating and stabilizing features to the guide 426. Regardless of thepresence of locating protrusions 538, however, it is contemplated thatat least a portion of the guide 426 will be in contact with theacetabular cup implant 216 in a predetermined orientation when thestructures have achieved the configuration shown in FIGS. 14-15. Thelocating protrusion 538 shown in FIG. 15 nests into a central one of thefastener apertures 220, which also holds a central landmark 1254.Accordingly, this locating protrusion 538 doubles as a guiding aperture434 and can accept a fastener or other structure inserted thereinto.

One example sequence of use for any configuration of the firstembodiment of the present invention is shown in FIGS. 16-21. In FIG. 16,the acetabular cup implant 216 has been placed in the acetabulum 110. Itshould be understood that the acetabular cup implant 216 is notnecessarily in the predetermined implant orientation at this point inthe procedure. The guide 426 is then placed atop the acetabular cupimplant 216 with the lower guide surface 528 in mating contact(optionally with the assistance of one or more locating protrusions 538)with the upper implant surface 222 in the predetermined relativeguide/implant orientation.

The guide 426 and the acetabular cup implant 216 are then shifted asdesired, independently or concurrently and optionally with the use ofone or more orienting features 440 and/or orienting indicators 442, asdescribed above with reference to FIGS. 4-8, until the acetabular cupimplant is in the predetermined implant orientation and the guide is ina predetermined guide orientation. This view is shown in FIG. 17.

Once the acetabular cup implant 216, guide 426, and acetabulum 110 haveachieved the relative positioning and configuration shown in FIG. 17,the user can prepare for installation of the fasteners 1150 in thepreselected aperture locations (indicated by the placement of theguiding apertures 434 on the guide) and along the target trajectories536. For example, when fastener cavities 1956, pilot or otherwise, areto be pre-drilled to receive the fasteners 548, at least one guidingaperture 434 may be configured to guide a surgical tool 1858 through acorresponding fastener aperture 220 and into the patient tissue alongthe target trajectory 536 to create the fastener cavity in the patienttissue, as shown in FIGS. 18-20. Though omitted here for clarity, aguiding sleeve (not shown) may be placed into the guiding aperture 434(and optionally extend into the corresponding fastener aperture 220) toprotect the guide 426 and/or the acetabular cup implant 216 from theforces (e.g., rotational) exerted by the surgical tool 1858. Whenpresent, the guiding sleeve may also serve as an extension of theguiding aperture 434 to emphasize the target trajectory 536 and helpmaintain collinearity of the fastener cavity 1956 with the targettrajectory. As another example, not shown, when the fastener 1150 doesnot require a pre-drilled hole (e.g., the fastener is a self-tappingscrew or a nail), at least one guiding aperture 434 may be configured toguide the fastener itself through a corresponding fastener aperture 220and into the patient tissue along the target trajectory 536 into thefinal arrangement of FIG. 21.

In the former arrangement (i.e., guide 426 guides surgical tool 1858),the guide may be removed from the acetabular cup implant 216 once thefastener cavities 1956 are produced, such as in FIG. 20. The acetabularcup implant 216 is maintained in place while fasteners 1150 are theninstalled directly through the selected fastener apertures 220 (i.e.,those with associated fastener cavities already drilled) to secure theacetabular cup implant to the acetabulum 110, forming the finalarrangement shown in FIG. 21. Optionally, the fastener apertures 220 maybe countersunk (not shown) to accommodate each fastener head 2160 withinthe material of the acetabular shell 218 and present a substantiallysmooth upper implant surface 222. Alternately or additionally, at leastone fastener head 2160 could remain protruding from the acetabular shell218 above the upper implant surface 222, as shown in FIG. 21,particularly if such would be desirable in attaching another prostheticimplant structure (e.g., an acetabular liner, not shown) to theacetabular cup implant 216. As other options, the fasteners 1150 couldbe substantially headless or could have fastener heads 2160 whichinteract with the inner surface of the fastener apertures 220 to remainrecessed below the upper implant surface 222 while still providing asecuring function to the acetabular cup implant 216.

In the latter arrangement (i.e., guide 426 guides fastener[s] 1150), theguide may be configured to accommodate the fastener heads 2160, if any,before the guide is removed from the acetabular cup implant 216. Forexample, the guide 426 could be frangible and thus equipped for at leastpartial disassembly and removal when the fasteners 1150 have beensubstantially guided along the target trajectories 536. As anotherexample, the guiding apertures 434 could be elongate and configured tocreate a slot open to the lateral edge of the guide body 432, so thatthe guide 426 can be moved laterally out of engagement with theacetabular cup implant 216 without changing the trajectories of thepartially-inserted fasteners 1150 from the target trajectories 536.Regardless of the operation or structure employed, at least one of theguiding apertures 434, fastener apertures 220, and fasteners 1150 couldbe configured to allow removal of the guide 426 from the acetabular cupimplant 216, again without changing the trajectories of thepartially-inserted fasteners from the target trajectories 536. When thefasteners 1150 are left partially inserted at the time the guide 426 isremoved, the user may complete their insertion without the guidinginfluence of the guide; it will generally be desirable, however, thatthe guide not be removed until there is substantial certainty that thefasteners are adequately engaged with the patient tissue of the hip bone100 and will continue to follow their target trajectories 536 during theremaining insertion operation even without the guide being present.

Regardless of the way in which the guide 426 is removed, the acetabularcup implant 216 is anticipated to be securely fastened to the acetabulum110 at, or shortly after, the guide removal is accomplished. The usermay then continue with the surgical processes to complete theinstallation of the prosthetic implant and to conclude the surgicalprocedure as desired.

In summary, the guide 426 can assist the user with placement offasteners 1150 into a prosthetic implant and a patient tissue in adesired fashion by providing target trajectories 536 and aperture (thatis, insertion) locations for each fastener. Each target trajectory 536and each aperture location is preselected responsive to preoperativeimaging of the patient tissue, with each target trajectory and eachaperture location being preselected to facilitate placement of afastener 1150 into a stock prosthetic implant and the underlying patienttissue at a preselected fastener location and a preselected fastenertrajectory before and/or after removal of the guide 426 from the stockprosthetic implant. The guide 426 also may be configured to enter apredetermined orienting relationship, such as with the assistance of anorienting feature 440, with a natural or acquired landmark (not shown),such as a guide pin, wire, marking, and/or other location indicatorpreviously placed in a predetermined relationship with the patienttissue, to facilitate correct location of at least one target trajectory536 with respect to the patient tissue.

FIGS. 22-27 depict a guide 426′ according to a second embodiment of thepresent invention and related structures. The guide 426′ of FIGS. 25-27is similar to the guide 426 of FIGS. 4-10 and therefore, structures ofFIGS. 25-27 that are the same as or similar to those described withreference to FIGS. 4-10 have the same reference numbers with theaddition of a “prime” mark. Description of common elements and operationsimilar to those in the previously described first embodiment will notbe repeated with respect to the second embodiment. FIG. 22 is a partialperspective view of the scapula, with particular emphasis on the glenoidfossa 2262. A glenoid implant 2364, shown in FIGS. 23-24, is the stockprosthetic implant for use with a prosthetic shoulder replacementsurgery for the second embodiment of the present invention. This glenoidimplant 2364 happens to be a metaglene implant, which accepts aglenosphere component (not shown) in a known manner for a reverseshoulder prosthesis. The glenoid implant 2364 includes a lower implantsurface 224′, an upper implant surface 222′, and a plurality of fastenerapertures 220′ extending between the lower and upper implant surfaces.Certain configurations of the glenoid implant 2364 may also include animplant shaft 2466.

During installation of the glenoid implant 2364, a shaft aperture (notshown) is drilled into the patient tissue (here, the patient's glenoidfossa 2262) and the implant shaft 2466 is placed in the shaft aperturefor initial securement and stabilization before the fasteners 1150′ areinstalled. The implant shaft 2466 may act as a pivot point for rotationof the glenoid implant 2364 during movement of the glenoid implant intothe predetermined implant orientation, similar to the proceduredescribed above for the first embodiment. In this situation, the shaftaperture serves as a landmark 1254′ to communicate pre-operativelyplanned location information to the user during the surgical procedure.The implant shaft 2466 may also act to help stabilize the glenoidimplant 2364 on an ongoing basis, after conclusion of the describedsurgical procedure. The glenoid fossa 2262 could be reamed, cut,grafted, or otherwise altered from its native or pathologic state toaccept the glenoid implant 2364, as desired according to thepreoperative plan and/or an intraoperative decision.

Optionally, a landmark 1254′ such as the previously described guidewiremay be passed through the glenoid implant 2364 and into the patienttissue of the glenoid fossa 2262 through the use of a shaft aperture2368 passing through the implant shaft 2466. When the shaft aperture2368 is used in this manner, the landmark 1254′ may be placed first, tohelp locate the glenoid implant 2364 upon the glenoid fossa 2262, or thelandmark may be placed into a glenoid implant already in place on theglenoid fossa, to help with location of the guide 426′ upon the glenoidimplant.

The desire for use of one or more landmark(s) 1254′ and/or guide(s) 426′for the shoulder use environment stems from the relatively open plateauof the glenoid fossa 2262, on which the glenoid implant 2364 can bepositioned and oriented a number of different ways. In contrast, theacetabulum 110 tends to naturally cup and settle an appropriately sizedacetabular cup implant 216, inserted by a knowledgeable user, into oneof a few positions, and the rotational orientation of the acetabular cupimplant can then be refined through use of the orienting feature(s) 440,when present. Particularly in a revision situation, due to anatomicabnormalities, it may be difficult to position either of thesecomponents in the glenoid fossa 2262 or acetabulum 110, as the case maybe. This difficulty generally stems from bone loss or surgicalalteration of the patient tissue resulting in a loss of naturallandmarks.

A guide 426′ for use with the glenoid implant 2364 is shown in FIGS.25-27. As can be seen in FIG. 26, the guide 426′ includes a centralprotrusion 2670 configured to nest into the shaft aperture 2368 of theglenoid implant 2364. In the second embodiment, the fastener apertures220′ of the glenoid implant 2364 also serve to accept the locatingprotrusions 538′ of the guide 426′, which surround each of the fastenerapertures, as shown. The fastener apertures 220′ are optionallycountersunk to accept the locating protrusions 538′. When a countersunkfastener aperture 220′ is provided for a locating protrusion 538′,whether the countersunk feature is added by the user or originallyprovided by the implant manufacturer, the countersunk portion might alsoor instead be used to accept a fastener head 2160′ to provide a smoothupper implant surface 222′ with no protruding fastener heads whensecurement of the glenoid implant 958 to the patient tissue is complete.With reference to FIG. 26, the guiding apertures 434′ each can be seento be located on the lower guide surface 528′ in a position coincidentwith the fastener apertures 220′ on the upper implant surface 222′ whenthe guide 426′ is mated with the glenoid implant 2364 as shown in FIG.27 (in this Figure, the glenoid implant is located directly underneaththe guide 426′, as indicated by the dashed leader line). However, as canbe seen in FIGS. 25 and 27, the location of the fastener apertures 220′upon the upper guide surface 430′ is dictated by the target trajectory536′ defined by each fastener aperture and is patient-specific, beingpreselected responsive to preoperative imaging of the patient tissue.

An optional handling feature 2572 is indented into the upper guidesurface 430′ and is configured as a connection point for a handling tool(not shown), which may provide assistance with moving the guide 426′within the surgical field. Because the handling feature 2572 shown inthe figures is located collinearly with the implant shaft 2466, thehandling tool can be used to rotate the guide 426′ about an axis definedby the implant shaft—this axis, when present, is acting as a landmark1254′ by indicating information to the user regarding a pre-plannedlocation of the surgical site. While the handling feature 2572 shown isa void adapted to receive a hex-head driver, any suitable handlingfeature may protrude from, and/or be recessed into, any surface of theguide 426′ and may have any desired shape or configuration. Sometimesthe available maneuvering space in a surgical field is relativelyrestricted, and it may be useful for a forceps, hex wrench (perhaps witha frictional fit or other feature to nest into the handling feature2572), Kocher tool, hemostat, or other user-manipulated handling tool(not shown) to selectively interact with the handling feature to holdthe guide 426′ steady and/or to move the guide to a desired position.One or more features, such as indents, apertures, cavities, lugs,undercuts, or any other suitable structures could be provided to thehandling feature 2572 or to any other structure of the guide 426′ tofacilitate gripping of the guide by any handling tool, in general,and/or by a particular handling tool.

In use, the guide 426′ of the second embodiment operates similarly tothe guide 426 of the first embodiment. The glenoid implant 2364 of FIGS.23-24 is placed upon the glenoid fossa 2262 surface. Optionally, animplant-receiving aperture (not shown) may have been previously drilledin the glenoid fossa 2262 surface—if so, the implant shaft 2466 isinserted into the implant-receiving aperture as a part of placing thelower implant surface 224′ in contact with the patient tissue. The guide426′ is placed atop the glenoid implant 2364 with the lower guidesurface 528′ in contact with the upper implant surface 222′. Whenpresent, the locating protrusions 538′ of the guide 426′ may mate withthe fastener apertures 220′ of the glenoid implant 2364.

Once the glenoid implant 2364 and guide 426′ are mated together in thepredetermined relative guide/implant orientation atop the glenoid fossa2262 surface, the glenoid implant and guide can be moved concurrently tomove both the guide and the glenoid implant into predetermined guide andimplant orientations with respect to the glenoid surface. In otherwords, engagement between the guide 426′ and the glenoid implant 2364causes forces exerted upon the guide to be transferred to the glenoidimplant, and the user can move both the glenoid implant and the guideconcurrently by moving just the guide. For example, and presuming thatthe glenoid implant 2364 includes an implant shaft 2466 received into animplant-receiving aperture in the glenoid fossa 2262 surface, aclockwise force (indicated by clockwise arrow 2774 in FIG. 27) exertedupon the orienting feature 440′ will pivot the guide 426′—and thus themated glenoid implant—about the implant shaft.

The guide 426′ and mated glenoid implant 2364 may be rotated, forexample, until the orienting indicator 442′ achieves a predeterminedsignaling relationship with a landmark 1254′ such as the depicted guidepin. Accordingly, the guide 426′ can rotate the glenoid implant 2364into a predetermined implant orientation with respect to the glenoidfossa 2262 surface. As another example, the guide 426′ and mated glenoidimplant 2364 could be placed with the orienting indicator 442′ at, orclose to, the predetermined signaling relationship with the landmark1254′ before the glenoid implant comes into contact with the glenoidfossa 2262. In this latter situation, the glenoid implant 2364 could beguided into the predetermined implant orientation concurrently withbeing brought into contact with the glenoid fossa 2262 as the orientingindicator 442′ slides along the length of the guide pin via a rail-likedynamic guiding technique

Once the guide 426′ is mated to the glenoid implant 2364 and theorienting feature 440′ has been rotated or otherwise moved into thepredetermined orienting relationship with the previously placed landmark1254, the glenoid implant will have achieved the predetermined implantorientation. The desired fastener 1150′ locations with respect to theglenoid fossa 2262 surface will correspond to one or more of thefastener apertures 220′ of the glenoid implant 2364 when the glenoidimplant has reached the predetermined implant orientation. A surgicaltool 1858′ and/or fasteners 1150′ can then be guided along the targettrajectories 536′ by the guide 426′ through the fastener apertures 220′,the guide 426′ can be removed at an appropriate stage in the glenoidimplant 2364 securement procedure, and installation of the glenoidimplant and the remainder of the prosthetic shoulder assembly can thenproceed apace.

FIGS. 28-29 depict a guide 426″ according to a third embodiment of thepresent invention. The guide 426″ of FIGS. 28-29 is similar to the guide426 of FIGS. 4-10 and therefore, structures of FIGS. 28-29 that are thesame as or similar to those described with reference to FIGS. 4-10 havethe same reference numbers with the addition of a double “prime” mark.Description of common elements and operation similar to those in thepreviously described first and second embodiments will not be repeatedwith respect to the third embodiment.

In FIGS. 28-29, a patient tissue (here, a long bone 2876) having amalunion problem has previously been resected, optionally with theassistance of an aid such as the aforementioned guide disclosed inco-pending U.S. patent application No. to be determined, filed Oct. 27,2011, titled “System and Method for Association of a Guiding Aid with aPatient Tissue” and claiming priority to U.S. Provisional PatentApplication No. 61/408,359, filed Oct. 29, 2010 and titled “System andMethod for Association of a Guiding Aid with a Patient Tissue”, theentire contents of both of which are incorporated herein by reference.The resected tissue has been removed, and the long bone 2876 has beencollapsed along the resection line 2878. A stock prosthetic implant,shown here as bone plate 2880, has been placed in a predeterminedimplant orientation with respect to the long bone 2876. A guide 426″ hasbeen placed into a predetermined guide/implant orientation with respectto the bone plate 2880. The guide 426″ includes at least one guidingaperture 434″ at a predetermined aperture location, the guidingaperture(s) 434″ each defining a target trajectory 536. After achievingthe positioning shown in the Figures, the guide 426″ is used to aid withthe attachment of the bone plate 2880 to the long bone 2876 in a manneranalogous to those described above with reference to the first andsecond embodiments of the present invention.

The above description presumes that the guide 426 is removed from theprosthetic implant component before completion of the surgery. It iscontemplated, nevertheless, that the guide 426 and/or a stock prostheticimplant component could be configured for maintenance of the guidewithin the body, perhaps as a part of the completely installedprosthetic implant structure. One way in which this might beaccomplished, using as an example the aforementioned acetabular cupimplant 216, is for the fastener apertures 220 to be located in an areaof the acetabular shell 218 which has a recessed upper implant surface222 to accept the guide 426 in a manner which results in a substantiallyeven-profiled composite inner shell surface for smooth contact with thefemoral implant component, this composite inner shell surface beingcomprised of the upper implant surface in combination with the upperguide surface 430.

It is contemplated that the guide 426 could be used with an instrumentor related components such as those disclosed in co-pending U.S. patentapplication No. to be determined, filed Oct. 27, 2011, titled “Systemand Method for Assisting with Arrangement of a Stock Instrument withRespect to a Patient Tissue” and claiming priority to U.S. ProvisionalPatent Application No. 61/408,376, filed Oct. 29, 2010 and titled“System and Method for Assisting with Arrangement of a Stock Instrumentwith Respect to a Patient Tissue”, the entire contents of both of whichare incorporated herein by reference.

While aspects of the present invention have been particularly shown anddescribed with reference to the preferred embodiment above, it will beunderstood by those of ordinary skill in the art that various additionalembodiments may be contemplated without departing from the spirit andscope of the present invention. For example, the specific methodsdescribed above for using the guide 426 are merely illustrative; one ofordinary skill in the art could readily determine any number of tools,sequences of steps, or other means/options for placing theabove-described apparatus, or components thereof, into positionssubstantially similar to those shown and described herein. Any of thedescribed structures and components could be integrally formed as asingle piece or made up of separate sub-components, with either of theseformations involving any suitable stock or bespoke components and/or anysuitable material or combinations of materials; however, the chosenmaterial(s) should be biocompatible for most applications of the presentinvention. The mating relationships formed between the describedstructures need not keep the entirety of each of the “mating” surfacesin direct contact with each other but could include spacers or holdawaysfor partial direct contact, a liner or other intermediate member forindirect contact, or could even be approximated with intervening spaceremaining therebetween and no contact. Though certain componentsdescribed herein are shown as having specific geometric shapes, allstructures of the present invention may have any suitable shapes, sizes,configurations, relative relationships, cross-sectional areas, or anyother physical characteristics as desirable for a particular applicationof the present invention. An adhesive (such as, but not limited to, bonecement) could be used in conjunction with the system and methoddescribed herein. The guide 426 may include a plurality of structurescooperatively forming the base body and temporarily or permanentlyattached together in such a manner as to permit relative motion (e.g.,pivoting, sliding, or any other motion) therebetween. Any structures orfeatures described with reference to one embodiment or configuration ofthe present invention could be provided, singly or in combination withother structures or features, to any other embodiment or configuration,as it would be impractical to describe each of the embodiments andconfigurations discussed herein as having all of the options discussedwith respect to all of the other embodiments and configurations. Asleeve (not shown) could be provided to surround the fastener 1150and/or surgical tool 1858 during insertion into at least one of theguiding aperture 434 and the fastener aperture 220—the sleeve (whenpresent) could extend at least partially into the guiding apertureand/or the fastener aperture, and the sleeve could have variable wallthickness about a circumference thereof in order to place the elongatebody in an offset relationship with a centerline of the relevantaperture(s). An adhesive (such as, but not limited to, bone cement)could be used in conjunction with the system and method describedherein. Any of the components described herein could have a surfacetreatment (e.g., texturization, notching, etc.), material choice, and/orother characteristic chosen to provide the component with a desiredinteraction property (e.g., tissue ingrowth, eluting of a therapeuticmaterial, etc.) with the surrounding tissue. A device or methodincorporating any of these features should be understood to fall underthe scope of the present invention as determined based upon the claimsbelow and any equivalents thereof.

Other aspects, objects, and advantages of the present invention can beobtained from a study of the drawings, the disclosure, and the appendedclaims.

1. A method of attaching a stock prosthetic implant to a patient tissue,the stock prosthetic implant including a plurality of fastener aperturesextending therethrough, the method comprising the steps of: placing alower implant surface of the stock prosthetic implant into contact withthe patient tissue in a predetermined implant orientation; providing aguide having a lower guide surface contoured to substantially mate withat least a portion of an upper implant surface of the stock prostheticimplant, an upper guide surface spaced longitudinally apart from thelower guide surface by a guide body, and at least one guiding apertureextending through the guide body between the upper and lower guidesurfaces at a predetermined aperture location with respect to the guidebody; defining a predetermined target trajectory through the guide bodywith a chosen guiding aperture, at least one of the target trajectoryand the aperture location of each guiding aperture being preselectedresponsive to preoperative imaging of the patient tissue; placing thelower guide surface into mating contact with at least a portion of theupper implant surface in a predetermined relative guide/implantorientation; placing the chosen guiding aperture into a collinearrelationship with a chosen one of the fastener apertures; and at leastone of guiding a surgical tool through the chosen guiding aperture andthe corresponding chosen fastener aperture and inserting the surgicaltool into the patient tissue along the target trajectory to create afastener cavity in the patient tissue; and guiding a fastener throughthe chosen fastener aperture and into the patient tissue along thetarget trajectory.
 2. The method of claim 1, including the steps of:removing the surgical tool from the guide; removing the guide from thestock prosthetic implant; placing at least one fastener through thechosen fastener aperture and inserting the fastener into thecorresponding fastener cavity without placing the at least one fastenerthrough the guiding aperture; and securing the fastener within thefastener cavity to maintain the stock prosthetic implant in thepredetermined implant orientation.
 3. The method of claim 1, wherein thestep of placing the lower guide surface into mating contact with atleast a portion of the upper implant surface includes the steps of:providing at least one locating protrusion extending from the lowerguide surface toward the upper implant surface; and nesting the locatingprotrusion into at least one of a preselected one of the fastenerapertures and a location aperture of the upper implant surface.
 4. Themethod of claim 1, including the step of limiting a depth of insertionof at least one of the surgical tool and the fastener into the patienttissue.
 5. The method of claim 1, wherein the step of providing a guideincludes at least one of the steps of: custom-manufacturing the guideresponsive to at least one of preoperative imaging of the patient tissueand preoperative selection of the stock prosthetic implant; andmodifying a stock guide responsive to at least one of preoperativeimaging of the patient tissue and preoperative selection of the stockprosthetic implant.
 6. The method of claim 1, including the step ofpreselecting each target trajectory and each aperture location tofacilitate placement of the fastener into the stock prosthetic implantand the underlying patient tissue at a preselected fastener location anda preselected fastener trajectory after removal of the guide from thestock prosthetic implant.
 7. The method of claim 1, including the stepsof: affixing at least one landmark to the patient tissue at apredetermined landmark location chosen responsive to preoperativeimaging of the patient tissue; and using the at least one landmark toassist with at least one of the steps of placing a lower implant surfaceof the stock prosthetic implant into contact with the patient tissue,placing the lower guide surface into mating contact with at least aportion of the upper implant surface, and placing the chosen guidingaperture into a collinear relationship with a chosen one of the fastenerapertures.
 8. The method of claim 1, wherein the step of placing a lowerimplant surface of the stock prosthetic implant into contact with thepatient tissue in a predetermined implant orientation includes the stepsof: providing an orienting feature on the guide; affixing at least onelandmark to the patient tissue at a location spaced from a location ofimplantation of the stock prosthetic implant; placing the lower guidesurface into mating contact with at least a portion of the upper implantsurface; and repositioning the guide and mated implant to bring theorienting feature into a predetermined orienting relationship with thelandmark.
 9. The method of claim 8, wherein the orienting featureincludes an orienting indicator, and the step of repositioning the guideand mated implant to bring the orienting feature into a predeterminedorienting relationship with the landmark includes the step ofrepositioning the guide and mated implant to achieve a predeterminedsignaling relationship between the landmark and the orienting indicator.10. The method of claim 8, wherein the step of repositioning the guideand mated implant to bring the orienting feature into a predeterminedorienting relationship with the landmark includes the step of moving thestock prosthetic implant and the guide concurrently to move both thestock prosthetic implant into the predetermined implant orientation andthe guide into the predetermined guide orientation.
 11. A guide forassisting with attachment of a stock prosthetic implant to a patienttissue, the guide comprising: a lower guide surface configured tocontact an upper implant surface of the stock prosthetic implant when alower implant surface of the stock prosthetic implant is in contact withthe patient tissue, at least a portion of the lower guide surface beingcontoured to substantially mate with at least a portion of the upperimplant surface; an upper guide surface spaced longitudinally apart fromthe lower guide surface by a guide body, the upper guide surface beingaccessible to a user when the lower guide surface is in contact with theupper implant surface; and at least one guiding aperture extendingthrough the guide body between the upper and lower guide surfaces at apredetermined aperture location with respect to the guide body, the atleast one guiding aperture defining a predetermined target trajectorythrough the guide body, and the at least one guiding aperture beingcollinear with a corresponding at least one fastener aperture in thestock prosthetic implant when the lower guide surface is mated with theupper implant surface; wherein at least one of the target trajectory andthe aperture location of each guiding aperture is preselected responsiveto preoperative imaging of the patient tissue.
 12. The guide of claim11, wherein both the lower guide surface and the upper implant surfaceare concave in profile.
 13. The guide of claim 11, wherein both thelower guide surface and the upper implant surface are convex in profile.14. The guide of claim 11, wherein the stock prosthetic implant includesa predetermined number of fastener apertures, and the guide includes apredetermined number of guiding apertures which is no more than thepredetermined number of fastener apertures, each guiding aperture beingcollinear with a predetermined one of the fastener apertures when thelower guide surface is mated with the upper implant surface.
 15. Theguide of claim 14, including at least one locating protrusion extendingfrom the lower guide surface toward the upper implant surface, thelocating protrusion being configured to nest into a preselected one ofthe fastener apertures.
 16. The guide of claim 11, wherein at least oneguiding aperture is configured to guide a surgical tool through acorresponding fastener aperture and into the patient tissue along thetarget trajectory to create a fastener cavity in the patient tissue. 17.The guide of claim 16, including at least one depth limiting featureconfigured to prevent further motion of at least one of a fastener andthe surgical tool along the target trajectory and into the patienttissue past a predetermined depth.
 18. The guide of claim 11, whereinthe upper guide surface includes at least one orienting feature, theorienting feature being configured to guide the user in placing theguide in a predetermined relative guide/implant orientation with thestock prosthetic implant.
 19. The guide of claim 11, being at least oneof custom-manufactured and modified from a stock guide, responsive to atleast one of preoperative imaging of the patient tissue and preoperativeselection of the stock prosthetic implant.
 20. The guide of claim 11,wherein each target trajectory and each aperture location is preselectedresponsive to preoperative imaging of the patient tissue, with eachtarget trajectory and each aperture location being preselected tofacilitate placement of a fastener into the stock prosthetic implant andthe underlying patient tissue at a preselected fastener location and apreselected fastener trajectory after removal of the guide from thestock prosthetic implant.
 21. The guide of claim 11, including anorienting feature, the orienting feature entering a predeterminedorienting relationship with a previously placed landmark while the lowerguide surface is in mating contact with at least a portion of the upperimplant surface in a predetermined relative guide/implant orientation.22. The guide of claim 21, wherein the orienting feature includes anorienting indicator, and the orienting indicator achieves apredetermined signaling relationship with the landmark while the guideand stock prosthetic implant are in the predetermined relativeguide/implant orientation.
 23. The guide of claim 21, wherein the stockprosthetic implant and the guide are moved concurrently to move both theguide and stock prosthetic implant into predetermined guide and implantorientations with respect to the patient tissue.
 24. The guide of claim11, wherein at least one locating protrusion extends from the lowerguide surface and is configured to nest into a location aperture of theupper implant surface to assist with mating of the lower guide surfacewith at least a portion of the upper implant surface.
 25. A guide forassisting with attachment of a stock prosthetic implant to a patienttissue, the guide comprising: a lower guide surface configured tocontact an upper implant surface of the stock prosthetic implant when alower implant surface of the stock prosthetic implant is in contact withthe patient tissue, the lower guide surface being contoured tosubstantially mate with at least a portion of the upper implant surface;an upper guide surface spaced longitudinally apart from the lower guidesurface by a guide body, the upper guide surface being accessible to auser when the lower guide surface is in contact with the upper implantsurface; and an orienting feature; wherein the orienting feature isconfigured to enter a predetermined orienting relationship with apreviously placed landmark while the lower guide surface is in matingcontact with at least a portion of the upper implant surface in apredetermined relative guide/implant orientation.
 26. The guide of claim25, wherein both the lower guide surface and the upper implant surfaceare concave in profile.
 27. The guide of claim 25, wherein both thelower guide surface and the upper implant surface are convex in profile.28. The guide of claim 25, wherein the stock prosthetic implant includesa predetermined number of fastener apertures, and the guide includes atleast one locating protrusion extending from the lower guide surfacetoward the upper implant surface, the locating protrusion beingconfigured to nest into a preselected one of the fastener apertures. 29.The guide of claim 25, being at least one of custom-manufactured andmodified from a stock guide, responsive to at least one of preoperativeimaging of the patient tissue and preoperative selection of the stockprosthetic implant.
 30. The guide of claim 25, wherein the orientingfeature includes an orienting indicator, and the orienting indicatorachieves a predetermined signaling relationship with the landmark whilethe guide and stock prosthetic implant are in the predetermined relativeguide/implant orientation.
 31. The guide of claim 25, wherein the stockprosthetic implant and the guide are moved concurrently to move both theguide and stock prosthetic implant into predetermined guide and implantorientations with respect to the patient tissue.
 32. The guide of claim25, including at least one guide aperture extending through the guidebody between the upper and lower guide surfaces, the guide aperturebeing configured to accept a landmark placed in a predeterminedrelationship with the patient tissue.